| Date | Value |
|---|---|
| May 21, 2020 23:24 | 507 ppm |
| May 8, 2020 22:47 | 463 ppm |
| May 4, 2020 22:23 | 540 ppm |
| Apr 12, 2020 21:13 | 460 ppm |
| Apr 6, 2020 20:50 | 474 ppm |
| Mar 25, 2020 20:59 | 475 ppm |
| Mar 21, 2020 20:44 | 473 ppm |
| Mar 21, 2020 20:44 | 473 ppm |
| Mar 5, 2020 14:58 | 495 ppm |
| Mar 1, 2020 10:42 | 500 ppm |
| Feb 20, 2020 10:29 | 500 ppm |